diff --git a/target-ppc/op_helper.c b/target-ppc/op_helper.c
index 420059ca48..23704d0848 100644
--- a/target-ppc/op_helper.c
+++ b/target-ppc/op_helper.c
@@ -1295,6 +1295,10 @@ uint64_t helper_fmadd (uint64_t arg1, uint64_t arg2, uint64_t arg3)
                  float64_is_signaling_nan(farg3.d))) {
         /* sNaN operation */
         farg1.ll = fload_invalid_op_excp(POWERPC_EXCP_FP_VXSNAN);
+    } else if (unlikely((float64_is_infinity(farg1.d) && float64_is_zero(farg2.d)) ||
+                        (float64_is_zero(farg1.d) && float64_is_infinity(farg2.d)))) {
+        /* Multiplication of zero by infinity */
+        farg1.ll = fload_invalid_op_excp(POWERPC_EXCP_FP_VXIMZ);
     } else {
 #ifdef FLOAT128
         /* This is the way the PowerPC specification defines it */
@@ -1303,9 +1307,15 @@ uint64_t helper_fmadd (uint64_t arg1, uint64_t arg2, uint64_t arg3)
         ft0_128 = float64_to_float128(farg1.d, &env->fp_status);
         ft1_128 = float64_to_float128(farg2.d, &env->fp_status);
         ft0_128 = float128_mul(ft0_128, ft1_128, &env->fp_status);
-        ft1_128 = float64_to_float128(farg3.d, &env->fp_status);
-        ft0_128 = float128_add(ft0_128, ft1_128, &env->fp_status);
-        farg1.d = float128_to_float64(ft0_128, &env->fp_status);
+        if (unlikely(float128_is_infinity(ft0_128) && float64_is_infinity(farg3.d) &&
+                     float128_is_neg(ft0_128) != float64_is_neg(farg3.d))) {
+            /* Magnitude subtraction of infinities */
+            farg1.ll = fload_invalid_op_excp(POWERPC_EXCP_FP_VXISI);
+        } else {
+            ft1_128 = float64_to_float128(farg3.d, &env->fp_status);
+            ft0_128 = float128_add(ft0_128, ft1_128, &env->fp_status);
+            farg1.d = float128_to_float64(ft0_128, &env->fp_status);
+        }
 #else
         /* This is OK on x86 hosts */
         farg1.d = (farg1.d * farg2.d) + farg3.d;
@@ -1332,6 +1342,10 @@ uint64_t helper_fmsub (uint64_t arg1, uint64_t arg2, uint64_t arg3)
                  float64_is_signaling_nan(farg3.d))) {
         /* sNaN operation */
         farg1.ll = fload_invalid_op_excp(POWERPC_EXCP_FP_VXSNAN);
+    } else if (unlikely((float64_is_infinity(farg1.d) && float64_is_zero(farg2.d)) ||
+                        (float64_is_zero(farg1.d) && float64_is_infinity(farg2.d)))) {
+        /* Multiplication of zero by infinity */
+        farg1.ll = fload_invalid_op_excp(POWERPC_EXCP_FP_VXIMZ);
     } else {
 #ifdef FLOAT128
         /* This is the way the PowerPC specification defines it */
@@ -1340,9 +1354,15 @@ uint64_t helper_fmsub (uint64_t arg1, uint64_t arg2, uint64_t arg3)
         ft0_128 = float64_to_float128(farg1.d, &env->fp_status);
         ft1_128 = float64_to_float128(farg2.d, &env->fp_status);
         ft0_128 = float128_mul(ft0_128, ft1_128, &env->fp_status);
-        ft1_128 = float64_to_float128(farg3.d, &env->fp_status);
-        ft0_128 = float128_sub(ft0_128, ft1_128, &env->fp_status);
-        farg1.d = float128_to_float64(ft0_128, &env->fp_status);
+        if (unlikely(float128_is_infinity(ft0_128) && float64_is_infinity(farg3.d) &&
+                     float128_is_neg(ft0_128) == float64_is_neg(farg3.d))) {
+            /* Magnitude subtraction of infinities */
+            farg1.ll = fload_invalid_op_excp(POWERPC_EXCP_FP_VXISI);
+        } else {
+            ft1_128 = float64_to_float128(farg3.d, &env->fp_status);
+            ft0_128 = float128_sub(ft0_128, ft1_128, &env->fp_status);
+            farg1.d = float128_to_float64(ft0_128, &env->fp_status);
+        }
 #else
         /* This is OK on x86 hosts */
         farg1.d = (farg1.d * farg2.d) - farg3.d;
@@ -1369,6 +1389,10 @@ uint64_t helper_fnmadd (uint64_t arg1, uint64_t arg2, uint64_t arg3)
                  float64_is_signaling_nan(farg3.d))) {
         /* sNaN operation */
         farg1.ll = fload_invalid_op_excp(POWERPC_EXCP_FP_VXSNAN);
+    } else if (unlikely((float64_is_infinity(farg1.d) && float64_is_zero(farg2.d)) ||
+                        (float64_is_zero(farg1.d) && float64_is_infinity(farg2.d)))) {
+        /* Multiplication of zero by infinity */
+        farg1.ll = fload_invalid_op_excp(POWERPC_EXCP_FP_VXIMZ);
     } else {
 #if USE_PRECISE_EMULATION
 #ifdef FLOAT128
@@ -1378,9 +1402,15 @@ uint64_t helper_fnmadd (uint64_t arg1, uint64_t arg2, uint64_t arg3)
         ft0_128 = float64_to_float128(farg1.d, &env->fp_status);
         ft1_128 = float64_to_float128(farg2.d, &env->fp_status);
         ft0_128 = float128_mul(ft0_128, ft1_128, &env->fp_status);
-        ft1_128 = float64_to_float128(farg3.d, &env->fp_status);
-        ft0_128 = float128_add(ft0_128, ft1_128, &env->fp_status);
-        farg1.d= float128_to_float64(ft0_128, &env->fp_status);
+        if (unlikely(float128_is_infinity(ft0_128) && float64_is_infinity(farg3.d) &&
+                     float128_is_neg(ft0_128) != float64_is_neg(farg3.d))) {
+            /* Magnitude subtraction of infinities */
+            farg1.ll = fload_invalid_op_excp(POWERPC_EXCP_FP_VXISI);
+        } else {
+            ft1_128 = float64_to_float128(farg3.d, &env->fp_status);
+            ft0_128 = float128_add(ft0_128, ft1_128, &env->fp_status);
+            farg1.d = float128_to_float64(ft0_128, &env->fp_status);
+        }
 #else
         /* This is OK on x86 hosts */
         farg1.d = (farg1.d * farg2.d) + farg3.d;
@@ -1409,6 +1439,10 @@ uint64_t helper_fnmsub (uint64_t arg1, uint64_t arg2, uint64_t arg3)
                  float64_is_signaling_nan(farg3.d))) {
         /* sNaN operation */
         farg1.ll = fload_invalid_op_excp(POWERPC_EXCP_FP_VXSNAN);
+    } else if (unlikely((float64_is_infinity(farg1.d) && float64_is_zero(farg2.d)) ||
+                        (float64_is_zero(farg1.d) && float64_is_infinity(farg2.d)))) {
+        /* Multiplication of zero by infinity */
+        farg1.ll = fload_invalid_op_excp(POWERPC_EXCP_FP_VXIMZ);
     } else {
 #if USE_PRECISE_EMULATION
 #ifdef FLOAT128
@@ -1418,9 +1452,15 @@ uint64_t helper_fnmsub (uint64_t arg1, uint64_t arg2, uint64_t arg3)
         ft0_128 = float64_to_float128(farg1.d, &env->fp_status);
         ft1_128 = float64_to_float128(farg2.d, &env->fp_status);
         ft0_128 = float128_mul(ft0_128, ft1_128, &env->fp_status);
-        ft1_128 = float64_to_float128(farg3.d, &env->fp_status);
-        ft0_128 = float128_sub(ft0_128, ft1_128, &env->fp_status);
-        farg1.d = float128_to_float64(ft0_128, &env->fp_status);
+        if (unlikely(float128_is_infinity(ft0_128) && float64_is_infinity(farg3.d) &&
+                     float128_is_neg(ft0_128) == float64_is_neg(farg3.d))) {
+            /* Magnitude subtraction of infinities */
+            farg1.ll = fload_invalid_op_excp(POWERPC_EXCP_FP_VXISI);
+        } else {
+            ft1_128 = float64_to_float128(farg3.d, &env->fp_status);
+            ft0_128 = float128_sub(ft0_128, ft1_128, &env->fp_status);
+            farg1.d = float128_to_float64(ft0_128, &env->fp_status);
+        }
 #else
         /* This is OK on x86 hosts */
         farg1.d = (farg1.d * farg2.d) - farg3.d;